L28 turbo build

[Lebouis]

i have a n42 block and a p79 head, i plan on using a 280zx turbo manifold and a protunerz 90mm intake manifold. however as for the actual building the motor i’m kinda clueless and wanna know some info on how to properly build it and what parts i should use for it. My goal is 300 ish whp and around the same torque, i want it to be a daily street car that i can still have fun with. I live in cali so i gotta go through smog and i want to know what i need to do for it to pass. Any info helps and any recommendations work. Thank you 

[Lebouis]

one more thing to note is i wanna know what diff and trans i should go with for this build. Thank you 

[ZHoob2004]

I'm not particularly familiar with California smog inspections, but I was under the impression that if it's not an OE part and it doesn't have a carb number, then it's not going to pass, so your intake would disqualify you immediately.

 

That said, I understand you can get away with quite a lot depending on who you take the car to for an inspection. Might want to hold onto a stock intake and think of a way to swap it on in case you have any trouble with that.

 

Someone else can provide better information on the motor build, but iirc you don't need much for 300, maybe pistons? I've heard that the non-turbo pistons have weaker ring lands and you might as well benefit from the 50+ years of development that piston technology has had since these motors were new.

 

R200 diff should get you there just fine, LSD more so.

[NewZed]

13 hours ago, Lebouis said:

i have a n42 block and a p79 head, i plan on using a 280zx turbo manifold and a protunerz 90mm intake manifold. 

 

what year car

[Lebouis]

47 minutes ago, NewZed said:

 

what year car

1978

[AydinZ71]

I can cover the motor build part. As mentioned, unless you “know a guy”, all the mods I am describing will disqualify you during your periodic smog inspection.

 

for the motor build, you will need the following for sure:

 

1) larger injectors. 400cc is the lowest I believe you could go.

2) Intercoolers and associateD piping

3) independent EFI management

4) turbo with a T3 style turbine input flange. You will need to match your displacement and power goal to the right unit. GT30 would work. You will need an internal wastegate if using the stock exhaust manifold and downpipe 

5) not sure how well the P79 head will flow. Almost everyone running turbo’s I come across are using a P90 or P90a head. Do some more research On this.
6) BOV 

7) the block internals will work just fine for 300ft-lbs torque, except the NA pistons are a bit sketchy. Better off using forged pistons intended for a turbo car. The stock turbo pistons have the rings recessed lower on the piston to avoid the heat from combustion. NA pistons will probably work, but the rings may wear sooner.

8. ) need to adapt your oil pressure sender fitting  And add an oil line to the new turbo 

9) upgraded fuel pump like a way to 255

 

you need to tune BEFORE running more than 8psi. You will destroy your pistons in no-time if you attempt high boost and happen to have auto-detonation (pinging), usually caused by fuel starvation or a poor tune. 

 

[Lebouis]

3 minutes ago, AydinZ71 said:

I can cover the motor build part. As mentioned, unless you “know a guy”, all the mods I am describing will disqualify you during your periodic smog inspection.

 

for the motor build, you will need the following for sure:

 

1) larger injectors. 400cc is the lowest I believe you could go.

2) Intercoolers and associateD piping

3) independent EFI management

4) turbo with a T3 style turbine input flange. You will need to match your displacement and power goal to the right unit. GT30 would work. You will need an internal wastegate if using the stock exhaust manifold and downpipe 

5) not sure how well the P79 head will flow. Almost everyone running turbo’s I come across are using a P90 or P90a head. Do some more research On this.
6) BOV 

7) the block internals will work just fine for 300ft-lbs torque, except the NA pistons are a bit sketchy. Better off using forged pistons intended for a turbo car. The stock turbo pistons have the rings recessed lower on the piston to avoid the heat from combustion. NA pistons will probably work, but the rings may wear sooner.

8. ) need to adapt your oil pressure sender fitting  And add an oil line to the new turbo 

9) upgraded fuel pump like a way to 255

 

you need to tune BEFORE running more than 8psi. You will destroy your pistons in no-time if you attempt high boost and happen to have auto-detonation (pinging), usually caused by fuel starvation or a poor tune. 

 

so wait doing this wouldn’t allow me to pass smog? hmm i’ve had this sort of strange idea of building the motors internals and getting it prepped for smog but not putting the turbo manifold and using the stock intake manifold so it would be “n/a” and then after smog i just attach the turbo and all other accessories. would that work or would it just be a waste of time? because in my mind it makes sense to do that and then add the turbo after but if there’s a way i could turbo it and pass smog then it’s a win win 

[Lebouis]

alright after some investigating i’ve found out that the p79 and p90 head are almost identical in flow and whatever and that the only difference is the port shape and the little metal lining in the exhaust ports for emissions. but even tho it won’t be necessary for this build, wouldn’t a basic head porting do the trick for a turbo build? 

[Lebouis]

another thing i forgot to mention is that i would like to bore and stroke my engine to 3.0L but i’ve heard that the best way to do that is with a LD 28 crank but they’re incredibly rare and expensive, would i be able to use my stock crank for this?

[AydinZ71]

16 minutes ago, Lebouis said:

so wait doing this wouldn’t allow me to pass smog? hmm i’ve had this sort of strange idea of building the motors internals and getting it prepped for smog but not putting the turbo manifold and using the stock intake manifold so it would be “n/a” and then after smog i just attach the turbo and all other accessories. would that work or would it just be a waste of time? because in my mind it makes sense to do that and then add the turbo after but if there’s a way i could turbo it and pass smog then it’s a win win 

this might work during the first inspection, but it’s going to be a pain to swap back during your next inspection. I don’t know how detailed they look, but the aftermarket EFI will probably cause you to fail. According to the state of California, any non-CARB approved modification of the engine that can effect emissions is an automatic fail, regardless of the emissions recorded during the test. 

[Lebouis]

1 minute ago, AydinZ71 said:

this might work during the first inspection, but it’s going to be a pain to swap back during your next inspection. I don’t know how detailed they look, but the aftermarket EFI will probably cause you to fail. According to the state of California, any non-CARB approved modification of the engine that can effect emissions is an automatic fail, regardless of the emissions recorded during the test. 

so what ur saying is i have 3 choices to go with

option A) Go n/a and switch to weber carbs kit from zcardepot

option b) steal someone’s tags and put them on my plate or just move to some other state

or option C) go through the trouble of altering  my motor and electronics every time i get it inspected 

[AydinZ71]

2 minutes ago, Lebouis said:

another thing i forgot to mention is that i would like to bore and stroke my engine to 3.0L but i’ve heard that the best way to do that is with a LD 28 crank but they’re incredibly rare and expensive, would i be able to use my stock crank for this?

you can read through this:

 

http://zcsd.org/tech-articles/power-quest2.php

[AydinZ71]

4 minutes ago, Lebouis said:

so what ur saying is i have 3 choices to go with

option A) Go n/a and switch to weber carbs kit from zcardepot

option b) steal someone’s tags and put them on my plate or just move to some other state

or option C) go through the trouble of altering  my motor and electronics every time i get it inspected 

In California, you either need to know of an inspector personally who will make sure your car passes, or buy a pre-73 car. Many of us 240z Owners deliberately had this in mind. We don’t need to smog check. 
 

Option a) will not work for you. 78’ did not come with carbs. Must be OEM or CARB approved alternate. 

see al those tricked out modded cars at car shows? They are either paying off their inspector to force a pass, Out of state registration, or registered for off-road only

[Lebouis]

Just now, AydinZ71 said:

In California, you either need to know of an inspector personally who will make sure your car passes, or buy a pre-73 car. Many of us 240z Owners deliberately had this in mind. We don’t need to smog check. 
 

Option a) will not work for you. 78’ did not come with carbs. Must be OEM or CARB approved alternate. 

see al those tricked out modded cars at car shows? They are either paying off their inspector to force a pass, Out of state registration, or registered for off-road only

ok so changing my car to carbureted wouldn’t work either. But the out of state thing is also another thing i had in mind, how exactly does that work? ik it involves someone outside of california to buy ur car and then register it and then sell it back to you but that’s about it. what are the more specific details and wouldn’t my car already have to be complete if i wanted to do that? it’s still a sitting in my garage being gutted out rn

[NewZed]

Taking the advice of someone who has found a way around the law, or thinks he has, doesn't seem like a good idea.  Plus he has a 71 so he might think that he knows a guy, but his car gets a pass on most of the emissions rules.  Your 78 does not.  Better figure it out before you spend too much money.  Plus - new administration in D.C.

 

https://www.dmv.ca.gov/portal/vehicle-registration/smog-inspections/

 

Your vehicle does not need a smog inspection if your:

• Gasoline-powered vehicle is a 1975 year model or older (This includes motorcycles and trailers.)
• Diesel-powered vehicle is a 1997 and older year model OR with a Gross Vehicle Weight of more than 14,000 pounds.
• Powered by natural gas and weighs more than 14,000 pounds. 
• An electric vehicle.
• Gasoline-powered and less than four model years old

[AydinZ71]

3 hours ago, NewZed said:

Taking the advice of someone who has found a way around the law, or thinks he has, doesn't seem like a good idea.  Plus he has a 71 so he might think that he knows a guy, but his car gets a pass on most of the emissions rules.  Your 78 does not.  Better figure it out before you spend too much money.  Plus - new administration in D.C.

 

https://www.dmv.ca.gov/portal/vehicle-registration/smog-inspections/

 

Your vehicle does not need a smog inspection if your:

• Gasoline-powered vehicle is a 1975 year model or older (This includes motorcycles and trailers.)
• Diesel-powered vehicle is a 1997 and older year model OR with a Gross Vehicle Weight of more than 14,000 pounds.
• Powered by natural gas and weighs more than 14,000 pounds. 
• An electric vehicle.
• Gasoline-powered and less than four model years old

 

I’m confused. Are you referring to me? To be clear, I don’t know anyway around the law. I don’t “know a guy”. I have a pre-73 car intentionally so It is exempt from smog. Am I misunderstanding? 

[AydinZ71]

4 hours ago, Lebouis said:

ok so changing my car to carbureted wouldn’t work either. But the out of state thing is also another thing i had in mind, how exactly does that work? ik it involves someone outside of california to buy ur car and then register it and then sell it back to you but that’s about it. what are the more specific details and wouldn’t my car already have to be complete if i wanted to do that? it’s still a sitting in my garage being gutted out rn

sorry man. I don’t have any advice for you on that. I have never gamed the CA law personally. 

[Lebouis]

2 minutes ago, AydinZ71 said:

sorry man. I don’t have any advice for you on that. I have never gamed the CA law personally. 

yeah at this point i’m just thinking of moving to a different state and building the car how i want it and registering somewhere else 

[Lebouis]

4 minutes ago, AydinZ71 said:

sorry man. I don’t have any advice for you on that. I have never gamed the CA law personally. 

my only other option would have to be to go stock or find some way around it but i don’t like either of those options 

[NewZed]

5 hours ago, AydinZ71 said:

In California, you either need to know of an inspector personally who will make sure your car passes,

 

This looks like advice to me...